Many connectors have been designed and patented for connecting a windshield wiper blade to the side pin of a side pin windshield wiper arm wherein the side pin has a reduced diameter intermediate portion bounded by an enlarged outer end portion and an enlarged inner end portion to define a groove area therebetween. Single spring clips have been provided for seating in the reduced diameter groove area of the side pin so as to retain the blade on the wiper arm. One such device is shown and described in U.S. Pat. No. 3,750,227 in the name of George Hayhurst et al wherein a single hairspring-type pin is seated in a slot in the yoke of a wiper blade and has a portion bridging across the aperture in the yoke so as to seat in the groove area of the wiper arm side pin. Another prior art device has a flat spring transversing the aperture in the bridge, which spring seats in the side pin groove area to hold the blade to the wiper arm. A still further prior art device is shown in U.S. Pat. No. 3,866,259 in the name of E. F. Nichols et al, assigned to the common assignee of the present application, wherein a U-shaped spring is secured in the channel-shaped metal yoke of the blade superstructure so that an intermediate shaped portion of the spring intersects aligned apertures between the side walls of a channel and will seat in the reduced diameter groove area of the side pin to secure the blade on the wiper arm. In this latter construction, if one spring leg ruptured or otherwise failed, the other spring leg would retain the blade on the side pin until remedial action could be taken.
The single hairspring has in some instances ruptured to release the blade from the wiper arm, while the flat spring did not always properly seat in the reduced diameter groove area of the side pin. With respect to the U-shaped spring construction, the spring had to be attached by special means and was not readily adaptable to a yoke formed from molded plastic material. In all of the aforementioned constructions, incomplete assembly of the blade to the wiper arm occasionally resulted since no means was provided to ensure that the wiper arm side pin was completely inserted to operative position within the yoke aperture. Further, no means was provided to ensure that the yoke did not disengage the side pin except when the spring was affirmatively deflected to release the side pin and the yoke was specifically located in a position relative to the side pin allowing withdrawal of the side pin from the yoke.